/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.runtime.operators.drivers;

import org.apache.flink.api.common.functions.ReduceFunction;
import org.apache.flink.api.common.functions.RichReduceFunction;
import org.apache.flink.api.common.serialization.SerializerConfigImpl;
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.api.java.typeutils.TypeExtractor;
import org.apache.flink.runtime.operators.AllReduceDriver;
import org.apache.flink.runtime.operators.DriverStrategy;
import org.apache.flink.runtime.operators.testutils.DiscardingOutputCollector;
import org.apache.flink.runtime.util.EmptyMutableObjectIterator;
import org.apache.flink.runtime.util.RegularToMutableObjectIterator;
import org.apache.flink.types.IntValue;
import org.apache.flink.types.StringValue;
import org.apache.flink.util.MutableObjectIterator;

import org.junit.jupiter.api.Test;

import java.util.Arrays;
import java.util.List;

import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.fail;

@SuppressWarnings("serial")
class AllReduceDriverTest {

    @Test
    void testAllReduceDriverImmutableEmpty() {
        try {
            TestTaskContext<ReduceFunction<Tuple2<String, Integer>>, Tuple2<String, Integer>>
                    context =
                            new TestTaskContext<
                                    ReduceFunction<Tuple2<String, Integer>>,
                                    Tuple2<String, Integer>>();

            List<Tuple2<String, Integer>> data = DriverTestData.createReduceImmutableData();
            TypeInformation<Tuple2<String, Integer>> typeInfo =
                    TypeExtractor.getForObject(data.get(0));
            MutableObjectIterator<Tuple2<String, Integer>> input = EmptyMutableObjectIterator.get();
            context.setDriverStrategy(DriverStrategy.ALL_REDUCE);

            context.setInput1(input, typeInfo.createSerializer(new SerializerConfigImpl()));
            context.setCollector(new DiscardingOutputCollector<Tuple2<String, Integer>>());

            AllReduceDriver<Tuple2<String, Integer>> driver =
                    new AllReduceDriver<Tuple2<String, Integer>>();
            driver.setup(context);
            driver.prepare();
            driver.run();
        } catch (Exception e) {
            System.err.println(e.getMessage());
            e.printStackTrace();
            fail(e.getMessage());
        }
    }

    @Test
    void testAllReduceDriverImmutable() {
        try {
            {
                TestTaskContext<ReduceFunction<Tuple2<String, Integer>>, Tuple2<String, Integer>>
                        context =
                                new TestTaskContext<
                                        ReduceFunction<Tuple2<String, Integer>>,
                                        Tuple2<String, Integer>>();

                List<Tuple2<String, Integer>> data = DriverTestData.createReduceImmutableData();
                TypeInformation<Tuple2<String, Integer>> typeInfo =
                        TypeExtractor.getForObject(data.get(0));
                MutableObjectIterator<Tuple2<String, Integer>> input =
                        new RegularToMutableObjectIterator<Tuple2<String, Integer>>(
                                data.iterator(),
                                typeInfo.createSerializer(new SerializerConfigImpl()));

                GatheringCollector<Tuple2<String, Integer>> result =
                        new GatheringCollector<Tuple2<String, Integer>>(
                                typeInfo.createSerializer(new SerializerConfigImpl()));

                context.setDriverStrategy(DriverStrategy.ALL_REDUCE);
                context.setInput1(input, typeInfo.createSerializer(new SerializerConfigImpl()));
                context.setCollector(result);
                context.setUdf(new ConcatSumFirstReducer());

                AllReduceDriver<Tuple2<String, Integer>> driver =
                        new AllReduceDriver<Tuple2<String, Integer>>();
                driver.setup(context);
                driver.prepare();
                driver.run();

                Tuple2<String, Integer> res = result.getList().get(0);

                char[] foundString = res.f0.toCharArray();
                Arrays.sort(foundString);

                char[] expectedString = "abcddeeeffff".toCharArray();
                Arrays.sort(expectedString);

                assertThat(foundString).isEqualTo(expectedString);
                assertThat(res.f1).isEqualTo(78);
            }

            {
                TestTaskContext<ReduceFunction<Tuple2<String, Integer>>, Tuple2<String, Integer>>
                        context =
                                new TestTaskContext<
                                        ReduceFunction<Tuple2<String, Integer>>,
                                        Tuple2<String, Integer>>();

                List<Tuple2<String, Integer>> data = DriverTestData.createReduceImmutableData();
                TypeInformation<Tuple2<String, Integer>> typeInfo =
                        TypeExtractor.getForObject(data.get(0));
                MutableObjectIterator<Tuple2<String, Integer>> input =
                        new RegularToMutableObjectIterator<Tuple2<String, Integer>>(
                                data.iterator(),
                                typeInfo.createSerializer(new SerializerConfigImpl()));

                GatheringCollector<Tuple2<String, Integer>> result =
                        new GatheringCollector<Tuple2<String, Integer>>(
                                typeInfo.createSerializer(new SerializerConfigImpl()));

                context.setDriverStrategy(DriverStrategy.ALL_REDUCE);
                context.setInput1(input, typeInfo.createSerializer(new SerializerConfigImpl()));
                context.setCollector(result);
                context.setUdf(new ConcatSumSecondReducer());

                AllReduceDriver<Tuple2<String, Integer>> driver =
                        new AllReduceDriver<Tuple2<String, Integer>>();
                driver.setup(context);
                driver.prepare();
                driver.run();

                Tuple2<String, Integer> res = result.getList().get(0);

                char[] foundString = res.f0.toCharArray();
                Arrays.sort(foundString);

                char[] expectedString = "abcddeeeffff".toCharArray();
                Arrays.sort(expectedString);

                assertThat(foundString).isEqualTo(expectedString);
                assertThat(res.f1).isEqualTo(78);
            }
        } catch (Exception e) {
            System.err.println(e.getMessage());
            e.printStackTrace();
            fail(e.getMessage());
        }
    }

    @Test
    void testAllReduceDriverMutable() {
        try {
            {
                TestTaskContext<
                                ReduceFunction<Tuple2<StringValue, IntValue>>,
                                Tuple2<StringValue, IntValue>>
                        context =
                                new TestTaskContext<
                                        ReduceFunction<Tuple2<StringValue, IntValue>>,
                                        Tuple2<StringValue, IntValue>>();

                List<Tuple2<StringValue, IntValue>> data = DriverTestData.createReduceMutableData();
                TypeInformation<Tuple2<StringValue, IntValue>> typeInfo =
                        TypeExtractor.getForObject(data.get(0));
                MutableObjectIterator<Tuple2<StringValue, IntValue>> input =
                        new RegularToMutableObjectIterator<Tuple2<StringValue, IntValue>>(
                                data.iterator(),
                                typeInfo.createSerializer(new SerializerConfigImpl()));

                GatheringCollector<Tuple2<StringValue, IntValue>> result =
                        new GatheringCollector<Tuple2<StringValue, IntValue>>(
                                typeInfo.createSerializer(new SerializerConfigImpl()));

                context.setDriverStrategy(DriverStrategy.ALL_REDUCE);
                context.setInput1(input, typeInfo.createSerializer(new SerializerConfigImpl()));
                context.setCollector(result);
                context.setUdf(new ConcatSumFirstMutableReducer());

                AllReduceDriver<Tuple2<StringValue, IntValue>> driver =
                        new AllReduceDriver<Tuple2<StringValue, IntValue>>();
                driver.setup(context);
                driver.prepare();
                driver.run();

                Tuple2<StringValue, IntValue> res = result.getList().get(0);

                char[] foundString = res.f0.getValue().toCharArray();
                Arrays.sort(foundString);

                char[] expectedString = "abcddeeeffff".toCharArray();
                Arrays.sort(expectedString);

                assertThat(foundString).isEqualTo(expectedString);
                assertThat(res.f1.getValue()).isEqualTo(78);
            }
            {
                TestTaskContext<
                                ReduceFunction<Tuple2<StringValue, IntValue>>,
                                Tuple2<StringValue, IntValue>>
                        context =
                                new TestTaskContext<
                                        ReduceFunction<Tuple2<StringValue, IntValue>>,
                                        Tuple2<StringValue, IntValue>>();

                List<Tuple2<StringValue, IntValue>> data = DriverTestData.createReduceMutableData();
                TypeInformation<Tuple2<StringValue, IntValue>> typeInfo =
                        TypeExtractor.getForObject(data.get(0));
                MutableObjectIterator<Tuple2<StringValue, IntValue>> input =
                        new RegularToMutableObjectIterator<Tuple2<StringValue, IntValue>>(
                                data.iterator(),
                                typeInfo.createSerializer(new SerializerConfigImpl()));

                GatheringCollector<Tuple2<StringValue, IntValue>> result =
                        new GatheringCollector<Tuple2<StringValue, IntValue>>(
                                typeInfo.createSerializer(new SerializerConfigImpl()));

                context.setDriverStrategy(DriverStrategy.ALL_REDUCE);
                context.setInput1(input, typeInfo.createSerializer(new SerializerConfigImpl()));
                context.setCollector(result);
                context.setUdf(new ConcatSumSecondMutableReducer());

                AllReduceDriver<Tuple2<StringValue, IntValue>> driver =
                        new AllReduceDriver<Tuple2<StringValue, IntValue>>();
                driver.setup(context);
                driver.prepare();
                driver.run();

                Tuple2<StringValue, IntValue> res = result.getList().get(0);

                char[] foundString = res.f0.getValue().toCharArray();
                Arrays.sort(foundString);

                char[] expectedString = "abcddeeeffff".toCharArray();
                Arrays.sort(expectedString);

                assertThat(foundString).isEqualTo(expectedString);
                assertThat(res.f1.getValue()).isEqualTo(78);
            }
        } catch (Exception e) {
            System.err.println(e.getMessage());
            e.printStackTrace();
            fail(e.getMessage());
        }
    }
    // --------------------------------------------------------------------------------------------
    //  Test UDFs
    // --------------------------------------------------------------------------------------------

    private static final class ConcatSumFirstReducer
            extends RichReduceFunction<Tuple2<String, Integer>> {

        @Override
        public Tuple2<String, Integer> reduce(
                Tuple2<String, Integer> value1, Tuple2<String, Integer> value2) {
            value1.f0 = value1.f0 + value2.f0;
            value1.f1 = value1.f1 + value2.f1;
            return value1;
        }
    }

    public static final class ConcatSumSecondReducer
            extends RichReduceFunction<Tuple2<String, Integer>> {

        @Override
        public Tuple2<String, Integer> reduce(
                Tuple2<String, Integer> value1, Tuple2<String, Integer> value2) {
            value2.f0 = value1.f0 + value2.f0;
            value2.f1 = value1.f1 + value2.f1;
            return value2;
        }
    }

    public static final class ConcatSumFirstMutableReducer
            extends RichReduceFunction<Tuple2<StringValue, IntValue>> {

        @Override
        public Tuple2<StringValue, IntValue> reduce(
                Tuple2<StringValue, IntValue> value1, Tuple2<StringValue, IntValue> value2) {
            value1.f0.setValue(value1.f0.getValue() + value2.f0.getValue());
            value1.f1.setValue(value1.f1.getValue() + value2.f1.getValue());
            return value1;
        }
    }

    public static final class ConcatSumSecondMutableReducer
            extends RichReduceFunction<Tuple2<StringValue, IntValue>> {

        @Override
        public Tuple2<StringValue, IntValue> reduce(
                Tuple2<StringValue, IntValue> value1, Tuple2<StringValue, IntValue> value2) {
            value2.f0.setValue(value1.f0.getValue() + value2.f0.getValue());
            value2.f1.setValue(value1.f1.getValue() + value2.f1.getValue());
            return value2;
        }
    }
}
